Collaborative Research: Lead-210 and Polonium-210 as tracers for scavenging and export: GEOTRACES Pacific Meridional Section

合作研究：铅 210 和钋 210 作为清除和出口示踪剂：GEOTRACES 太平洋子午线部分

• 批准号: 1736612
• 负责人: Mark Stephens
• 金额: $ 24.46万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-15 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736612&HistoricalAwards=false
• 关键词: Collaborative; Research; Lead; 210; Polonium

The goal of the international GEOTRACES program is to understand the distributions of trace chemical elements and their isotopes in the oceans. These chemical species play important roles in the ocean as nutrients, tracers of current and past oceanographic processes, and as contaminants from human activity. Their biogeochemical cycling has direct implications for research in such diverse areas as the carbon cycle, climate change, and ocean ecosystems. This project will use measurement of two natural radionuclides -- lead-210 and polonium-210 -- to provide important information about the rates of processes that affect trace elements and isotopes (TEIs) that will be measured during a U.S. GEOTRACES expedition in the Pacific Ocean in 2018. The research proposed here will address key tasks formulated within the GEOTRACES Science Plan. Many processes in the ocean cannot be observed directly but tracers such as polonium-210 (half-life = 138 days) and lead-210 (half-life = 22.3 years) that have unique chemical properties and relevant decay timescales can be used to provide important constraints on their rates and pathways. The goals of this research are to: 1) use Pb-210, along with another project measuring Be-7, in aerosols and precipitation to characterize aerosol and TEI sources, 2) determine scavenging rates of particle-reactive TEIs through the water column using Po-210 and Pb-210, 3) use Po-210 / Pb-210 disequilibrium in the upper water column as a proxy for the sinking flux of particulate organic carbon (POC), and 4) use Pb-210as a tracer of the influence of hydrothermal processes on water column distributions of TEIs. This work will build on a database of Po/Pb distributions in the world ocean (and the Pacific Ocean, in particular) obtained through programs such as GEOSECS, GEOTRACES, and independent studies. A graduate student will be trained as part of this project. The lead investigator, Cochran, plans to incorporate information about GEOTRACES sampling strategies in the planning for a travelling exhibition on "The Oceans" through his adjunct appointment at the American Museum of Natural History (New York). Project partner Kadko plans to incorporate GEOTRACES work in an international graduate course through the Nippon Foundation, Partnership for Observation of the Global Oceans Center of Excellence.

国际地学研究计划的目标是了解海洋中痕量化学元素及其同位素的分布。这些化学物种在海洋中作为营养物、当前和过去海洋过程的示踪物以及人类活动的污染物在海洋中发挥着重要作用。它们的生物地球化学循环对碳循环、气候变化和海洋生态系统等不同领域的研究具有直接影响。该项目将使用对两种天然放射性核素--铅-210和钚-210--的测量，以提供有关影响痕量元素和同位素(TEI)的过程的速率的重要信息，这些过程将于2018年美国在太平洋进行的地理追踪探险期间进行测量。这里提出的研究将涉及地球物理轨道系统科学计划内制定的主要任务。海洋中的许多过程不能直接观测，但具有独特的化学性质和相关的衰变时间尺度的示踪剂，如钚-210(半衰期=138天)和铅-210(半衰期=22.3年)，可以用来对它们的速率和路径提供重要的限制。本研究的目标是：1)利用铅-210和另一个测量气溶胶和降水中BE-7的项目来表征气溶胶和TEI的来源；2)使用Po-210和Pb-210来确定水柱中颗粒反应性TEI的清扫率；3)使用上层水柱中的Po-210/Pb-210不平衡作为颗粒有机碳(POC)下沉通量的替代；以及4)使用Pb-210作为水热过程对TEI水柱分布影响的示踪剂。这项工作将建立在通过GEOSECS、GEOTRACES和独立研究等计划获得的世界海洋(特别是太平洋)Po/Pb分布数据库的基础上。一名研究生将作为该项目的一部分接受培训。首席调查员科克伦计划通过他在美国自然历史博物馆(纽约)的兼职工作，将关于GEOTRACES抽样战略的信息纳入“海洋”巡回展览的规划中。项目合作伙伴Kadko计划通过日本基金会、全球海洋观测伙伴关系和卓越中心，将GEOTRACES的工作纳入国际研究生课程。

项目成果

210 Pb and 7 Be as Coupled Flux and Source Tracers for Aerosols in the Pacific Ocean

210 Pb 和 7 Be 作为太平洋气溶胶的耦合通量和源示踪剂

• DOI: 10.1029/2022gb007378
• 发表时间: 2022
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Wei, Ziran;Cochran, J. Kirk;Horowitz, Evan;Fitzgerald, Patrick;Heilbrun, Christina;Kadko, David;Stephens, Mark;Marsay, Chris M.;Buck, Clifton S.;Landing, William M.
• 通讯作者: Landing, William M.